EXCHANGE 


The  Adsorption  of  Ammonia  by 
Silica  Gel 


DISSERTATION 

SUBMITTED    TO    THE   BOARD    OF    UNIVERSITY    STUDIES 

OF  THE  JOHNS  HOPKINS  UNIVERSITY  IN  CONFORMITY 

WITH  THE  REQUIREMENTS  FOR  THE  DEGREE 

OF  DOCTOR  OF  PHILOSOPHY 


BY 

LEVI  YORGEY  DAVIDHEISER 

BALTIMORE 

June,  1922 


EASTON,  PA.  : 

ESCHENBACH  PRINTING  COMPANY 
1922 


The  Adsorption  of  Ammonia  by 
Silica  Gel 


DISSERTATION 

SUBMITTED    TO    THE   BOARD    OF    UNIVERSITY    STUDIES 

OF  THE  JOHNS  HOPKINS  UNIVERSITY  IN  CONFORMITY 

WITH  THE  REQUIREMENTS  FOR  THE  DEGREE 

OF  DOCTOR  OF  PHILOSOPHY 


BY 

LEVI  YORGKY  DAVIDHEISER 

BALTIMORE 

June,  1922 


EASTON,  PA.: 
ESCHENBACH  PRINTING  COMPANY 

1922 


CONTENTS 

Acknowledgment 4 

Introduction 5 

Apparatus 6 

Material 6 

Procedure 6 

Table  I 7 

Figure  I 8 

Table  II 9 

Figure  II 9 

Figure  III 10 

Figure  IV 11 

Biography 13 


043931 


ACKNOWLEDGMENT 

The  author  wishes  to  express  his  thanks  and  appreciation  to  Dr.  W.  A. 
Patrick  under  whose  instruction  this  work  was  carried  on  for  the  aid  and 
suggestions  received. 

I  also  wish  to  take  this  opportunity  to  extend  my  sincere  thanks  to 
Drs.  Frazer,  Reid,  Lovelace  and  Thornton  for  their  kind  assistance  in  the 
laboratory  and  lecture  room. 


THE  ADSORPTION  OF  AMMONIA  BY  SILICA  GEL. 

This  investigation  is  a  continuation  of  the  studies  of  Patrick  of  adsorp- 
tion of  gases  and  vapors  by  silica  gel.  In  Gottingen  he  studied  the 
adsorption  of  ammonia,  sulfur  dioxide  and  carbon  dioxide.  Since  then 
many  improvements  in  experimental  technique  ha\e  been  introduced,  as 
well  as  radical  modifications  of  the  theoretical  treatment  of  the  experi- 
mental results.  The  experimental  method  and  an  outline  of  the  theoretical 
views  ha\e  been  given  in  a  paper  dealing  with  the  adsorption  of  sulfur 
dioxide.1 

The  adsorption  of  ammonia  was  studied  for  a  number  of  reasons.  In 
the  first  place,  this  gas,  in  the  measurements  made  in  Gottingen,  was 
found  to  be  more  strongly  adsorbed  than  sulfur  dioxide  although  the 
latter  exhibits  a  higher  critical  temperature.  In  the  second  place,  our 
previous  measurements  indicated  that  the  behavior  of  ammonia  was 
anomalous  from  the  standpoint  of  the  rate  at  which  equilibrium  was 
reached.  Again,  ammonia  is  extremely  soluble  in  water  and  it  was  there- 
fore hoped  that  by  a  careful  study  of  its  adsorption  by  silica  gel,  light 
would  be  thrown  on  the  question  as  to  the  nature  of  the  small  amount 
of  water  that  is  always  associated  with  the  gel.  Furthermore,  in  am- 
1  MacGavack  and  Patrick,  /.  Am.  Chem.  Soc.,  42,  946  (1920). 


monia  we  have  a  gas  that  has  been  the  subject  of  numerous  careful  in- 
vestigations, and  as  a  result  the  physical  constants,  such  as  vapor  pres- 
sure, density  and  surface  tension,  are  very  accurately  known.  This  latter 
point  is  especially  important  inasmuch  as  a  knowledge  of  the  above  con- 
stants is  necessary  for  the  testing  of  our  theoretical  views  as  to  the  course 
of  the  adsorption. 

In  the  following  measurements  of  the  adsorption  of  ammonia  by  silica 
gel,  it  will  be  shown  that  this  gas  is  not  anomalous  in  its  behavior,  either 
from  the  standpoint  of  the  extent  or  the  rate  of  the  adsorption,  the  earlier 
discrepancies  being  due  to  the  uncertain  water  and  acid  content  of  the 
gel.  Especial  study  was  made  of  the  influence  of  the  water  content  of 
the  gel  on  the  adsorption,  and  it  was  found  that  small  differences 
produced  large  variations  in  the  adsorptive  ability  of  the  material. 

Apparatus. — The  experimental  method  has  been  described  in  detail 
by  MacGavack  and  Patrick.1  To  give  an  idea  of  the  precision  attained, 
it  may  be  stated  that  the  volume  of  ammonia  was  measured  to  within 
0.005  cc.,  the  pressure  to  within  0.03  mm.,  and  the  temperature  of  the 
thermostat  regulated  so  as  not  to  vary  more  than  0.05°. 

Material.  — The  ammonia  used  was  purified  liquid  ammonia.  Com- 
mercial ammonia  was  treated  with  metallic  sodium  for  one  week,  and 
the  accumulated  gas  allowed  to  escape  at  intervals  of  12  hours.  The 
purified  sample  was  tested  by  allowing  a  small  stream  of  the  gas  to  bubble 
into  sulfuric  acid  contained  in  a  gas  buret  for  10  minutes;  as  no  residue 
was  shown  by  this  procedure  it  was  assumed  that  the  ammonia  was  free 
from  permanent  gases. 

The  silica  gel  was  an  ordinary  commercial  sample  that  was  further 
purified  by  treatment  with  nitric  acid  and  a  thorough  washing  with  dis- 
tilled water.  When  dried  in  a  vacuum  of  1  to  5  mm.  at  a  temperature 
of  300°  for  3  hours  the  gel  still  contained  5.21%  of  water,  and  further- 
more an  appreciable  amount  of  nitric  acid,  to  which  reference  will  be 
made  later. 

Procedure. — The  adsorption  apparatus  was  evacuated  by  means  of 
a  rotary  oil  pump  and  a  Gaede  mercury  pump,  connected  in  series.  Before 
any  gel  was  put  into  the  adsorption  bulb,  the  apparatus  was  thoroughly 
evacuated  and  then  swept  out  with  ammonia  and  evacuated  again  until 
the  MacLeod  gage  showed  no  pressure  after  standing  under  a  vacuum 
for  4S  hours.  The  gel  was  weighed  in  the  adsorption  bulb,  which  was 
then  directly  attached  to  the  apparatus  by  means  of  a  ground  joint,  and 
sealed  by  mercury.  The  pumps  were  always  started  before  the  stopcock 
between  tin  adsorption  bulb  and  the  main  apparatus  was  opened,  so  that 
the  air  in  tin-  bulb  would  have-  k-ss  rhauce  to  become  adsorbed  on  the  walls 
of  the  apparatus.  The  heating  of  tin-  adsorption  bulb  was  started  at  the 
same  time,  care  briiijj  taken  not  to  heat  the  gel  to  a  higher  temperature 


than  that  at  which  it  was  prepared,  so  that  the  water  content  might  not 
be  disturbed.  The  evacuation  was  continued  until  the  MacLeod  gage 
showed  no  pressure,  usually  from  3  to  8  hours,  at  a  temperature  from 
290°  to  300°. 

In  the  beginning  it  was  found  almost  impossible  to  make  two  determ- 
inations that  would  agree.  After  a  considerable  number  of  measure- 
ments had  been  made  at  30°,  a  few  were  found  to  check  fairly  well.  How- 
ever, a  number  of  measurements  made  at  40  °  showed  that  the  gel  exhibited 
greater  adsorptive  ability  at  this  temperature  than  at- 30°.  Such  in- 
consistent and  disturbing  results  led  us  to  stop  and  thorougly  inspect 
our  apparatus  and  method  of  procedure.  The  apparatus  was  first  exam- 
ined for  leaks.  It  was  thoroughly  evacuated  and  allowed  to  stand  for 
one  week,  at  the  end  of  which  the  MacLeod  gage  showed  no  increase  of 
pressure.  The  ammonia  was  again  examined  and  no  foreign  gases  found. 
Another  series  of  measurements  was  made  at  30°  in  which  great  care 
was  taken  that  all  manipulations  should  be  as  nearly  identical  as  possible. 
The  electric  furnace,  in  which  the  adsorption  bulb  was  heated  during 
evacuation,  was  kept  constant  and  evacuation  continued  for  exactly  the 
same  length  of  time.  Under  these  conditions  checks  could  be  made  with 
but  little  variation.  This  proved  that  the  gel  did  not  remain  constant 

TABLE  I 
EXPERIMENTS  AT  0°,  30°,  40°  AND  100° 


Expt.  XX 

Temp.,  30°;  H2O  content,  4.93%;  Wt. 
of  gel.,  0.5739  g.;  D,  0.5939;  a,  18.03; 
I/TV,  0.2103;     #,57.30;     P0,  874.90. 
P  X/M          v 

0.07        26.82     0.034 
1.009      68.05    0.087 
37.726    126.66     0.161 

Expt.  XXIII 

Temp.,  40°;  H2O  content,  4.93%;  Wt. 
of  gel,  0  .5730  g.;  D,  0  .5769;  <r,  16.70; 
l/N,  0.2093;  K,  53.53;  P0,  1165.80. 


Expt.  XXV 

Temp.,    0°;    H2O   content,  4.93%;  Wt. 

of  gel,  0  .5744  g.;D,0  .6389;    <r,  25  .  94; 

Po,  322.10;  l/N,  0.2116;     K,  82.40. 


Pff/P0 

p 

X/M 

V      Pa/Po 

0.001443 

0 

.153 

58 

.77 

0 

.070 

0 

.012321 

0.020792 

8 

.116 

123 

.47 

0 

.147 

0 

.654614 

0.683757 

33 

.494 

168 

.59 

0 

.200 

2 

.697404 

58 

.653 

191 

.99 

0 

.228 

4 

.723902 

P      X/M 
0.218   36.42 
4.026   77.03 
20.987  101.06 
61.632  126.25 

V    P*/P0 
0.050  0.003123 
0.101  0.057672 
0.133  0.300622 
0.166  0.882887 

P  =  equilibrium  pressure  in  cm.  of 

mercury. 
X/M  =  cc.  of  ammonia  under 

standard  conditions   adsorbed  per 

g.  of  gel. 
V  =  cc.  of  liquid  ammonia  ad- 

sorbed. 


Expt.  XXIX 

Temp.,  100°;  H2O  content,  4.93%;  Wt. 
of  gel,   0.5737  g.;  D,  0.4589;  a,  6 .  5 
I/TV,  0  .2885;  K,  23  .07;  P0,  4693  .40. 
P  X/M  v  P<r/P0 

2.147         27.05     0.04473     0.00276 
13.805        52.22    0.08636     0.01912 
41.016        66.62    0.11017     0.05681 
Po    =  vapor  pressure  of  liquid  ammonia. 
D    =   density  of  liquid  ammonia, 
o-   =  surface  tension  of  liquid  ammonia. 


' 


8 


during  evacuation,  and  especially  was  this  true  when  the  pumps 
were  run  for  different  lengths  of  time.  All  the  experiments  recorded  in 
this  paper  were  made  under  conditions  that  allow  exact  duplication. 

In  Table  I  Experiments  XX, 
XXIII,  XXV  and  XXIX  are  re- 
corded the  results  of  the  measure- 
ments made  at  0°,  30°,  40°  and 
100°.  These  results  are  shown 
graphically  in  Fig.  1.  Equilibrium 
was  usually  reached  in  from  15  to 
30  minutes;  nevertheless  the  am- 
monia was  allowed  to  remain  in 
contact  with  the  gel  for  at  least  2 
hours.  As  more  ammonia  was  in- 
troduced and  the  pressure  increased, 
the  time  required  to  reach  equil- 


100 


80 


60 


40 


20 


20 


40 


60 


80 


ibrium  also  increased.  If  equil- 
ibrium was  not  reached  within  2 
hours  after  the  introduction  of  the 
first  amount  of  ammonia,  it  served 
as  an  indication  that  the  air  had 
not  been  completely  removed  from  the  apparatus.  It  was  found  that 
3  hours'  evacuation  with  the  adsorption  bulb  heated  to  290°  was  suf- 
ficient to  remove  all  the  air.  All  the  determinations  were  made 
under  these  conditions.  After  this  treatment  it  was  found  that  the  gel 
lost  0.28%  of  its  water  content.  When  this  treatment  was  continued  for 
8  hours  0.487%  of  the  water  was  removed.  The  gel  upon  analysis  was 
found  to  contain  0.437%  of  nitric  acid,  equivalent  to  5.23  cc.  of  am- 
monia. Of  course  as  the  gel  lost  some  of  its  water  content  some  of  the 
acid  also  was  lost. 

Inasmuch  as  our  preliminary  measurements  showed  that  the  water 
content  of  the  gel  was  a  most  important  factor  in  determining  the  extent 
of  the  adsorption,  an  effort  was  made  to.  prepare  a  gel  of  low  water  content. 
It  has  previously  been  thought  that  the  presence  of  the  water  was  very 
closely  associated  with  the  structure  of  the  material  and  the  removal 
of  the  water  below  2%  was  considered  undesirable.  The  subsequent 
results,  however,  indicate  that  such  views  are  unsound  and  that  it  is 
possible  to  obtain  a  gel  possessing  the  proper  adsorptive  structure  having 
only  0.33%  of  water. 

A  gel  containing  0.33%  of  water  was  prepared  by  heating  it  in  a  Pyrex 
glass  tube  through  which  a  current  of  dry  air  was  passed.  The  tube 
was  gradually  heated  with  a  Bunsen  flame  for  1  hour,  and  then 
in  the  flame  of  the  blast  lamp  for  2  hours  to  the  fusion  point  of  Py- 


9 


rex  glass.     During  this  process  the  gel  became  perfectly  clear  and  color- 
less. 

After  this  treatment  the  gel  was  tested  for  its  ability  to  adsorb  ammonia. 
It  was  rather  surprising  to  find  that  it  was  still  a  good  adsorbent  for  am- 
monia, adsorbing  on  an  average  about  53  cc.  less  per  gram  than  it  did 
before  this  drastic  treatment.  Two  isotherms  were  made,  one  at  0° 
and  one  at  30°.  Fig.  3  shows  the  graph  of  these  determinations  as  com- 
pared with  those  made  before  dehydrating  the  gel.  Table  II,  Experi- 
ments XXXI  and  XXXV  show  the  experimental  results. 


ACTION  OF 
Kxpt.  XXXI 

Temp.,  30°;  H2O  content,  0 .33%; 
of  gel,  0.5739  g.;  D,  0.5939;  a,  18 
l/N,  0.2487;  K,  21.33;  P0,  874. 

P  X/M  V 

1.293  24.49 

8.653  46.00 

18.933  57.08 

36.600  73.50 

59.697  83.01 


TABLE  II 
GEL  AFTER  HEAT  TREATMENT 

Expt.  XXXV 

Wt.  Temp.,  0°;  H2O  content,  0 .33%;  Wt. 

.03;  of  gel,  0. 5739  g.;D,0. 6389;  <r,  24.94; 

90.  l/N,  0.3948;  K,  28.765;  P0,  322.10. 

Pff/P0  P  X/M  V  P<r/P0 

0.05684  0.273091 

0.07287  0.544651 

0.09567  1.124572 

0.15145  3.708976 

0.17276  4.941874 


0.03113.  0.026646 
0.05878  0.178021 
0.07294  0.390173 
0.09392  0.754265 
0.10608  1.23024 

3.391   47.85 
6.763   61.35 
13.964   80.54 
46.056  127.50 
61.365  145.44 

2.6 


1.8 
1.4 


I 


«*JZ 


It  is  necessary  to  mention  a  phenomenon  that  was  observed  with  the 
measurements  made  at  100 °.  After  33.64  cc.  of  ammonia  had  been  brought 
over  0.5741  g.  of  gel  and  the  pressure  had  reached  a  value  of  287.35  mm., 
it  was  noticed  that  there  was  a  gradual  increase  in  the  pressure.  This 
increase  in  pressure  continued 
until  at  the  end  of  9  days  the 
pressure  in  the  apparatus  was 
471.40  mm.  Upon  cooling  the  2  2 
gel  to  0°,  the  pressure  imme- 
diately dropped  to  4.53  mm., 
while  heating  again  to  100° 
caused  an  immediate  rise  in 
pressure  to  the  value  of  471.40 
mm.  That  this  phenomenon 
is  in  some  way  associated  with 


<?• 


1.0    1.4   .18    0.2    0.6    1.0    1.4   1.8 


the  water  of  the  gel  is  indicated  by  the  fact  that  no  such  behavior  as 
outlined  above  was  exhibited  with  the  gel  containing  only  0.33%  of  water. 

Discussion  of  Results. 

The  various  isotherms  may  be  very  accurately  represented  by  the 
ordinary  empirical  adsorption  formula,  X/M  =  KP1'  .  In  Fig.  2  are 
plotted  the  logarithms  of  X/M  against  P,  and  from  the  straightness  of 
the  lines  it  is  apparent  that  the  above  formula  accurately  reflects  the 


10 


experimental  data.  Inasmuch  as  the  sulfur  dioxide  was  also  well  rep- 
resented by  the  same  relationship,  the  comparison  of  the  behavior  of 
ammonia  and  sulfur  dioxide  is  greatly  facilitated  by  use  of  the  values  of 
K  at  the  same  temperature.  In  the  following  table  are  given  the  values 
of  K  for  sulfur  dioxide  and  ammonia  obtained  with  a  gel  of  approximately 
the  same  water  content,  4.8%. 


0° 

30° 

40° 

100° 


NH3 
K 

82.40 
57.30 
53.53 
23.01 


S02 

K 

29.14 
12.93 

9.75 

1.12 


Inasmuch  as  the  significance  of  K  is  the  number  of  cubic  centimeters 
of  gas  adsorbed  by  1  g.  of  gel  at  a  pressure  of  1  cm.,  it  is  apparent  that 
ammonia  is  more  strongly  adsorbed  than  sulfur  dioxide  by  this  particular 
sample  of  gel. 

That  this  result  is  due  to  the  larger  solubility  of  ammonia  in  water,  is 

shown  by  the  fact  that  the  value  of 
K  for  ammonia  at  0°  decreased  from 
82.40  to  a  value  of  28.76  when  the 
water  con  tent  was  reduced  from  4.88% 
to  0.33%.  While  it  is  true  that  the 
adsorption  of  sulfur  dioxide  is  lessened 
by  a  diminution  of  the  water  con- 
tent of  the  gel,  the  effect  here  is  not 
so  pronounced  as  in  the  case  of  am- 
monia. It  will  be  observed  that 
with  a  gel  containing  0.33%  water 
content,  the  adsorption  of  ammonia 


10 


20 


20 


40 


60 


80 


is  lower  than  that  of  sulfur  dioxide 
in  a  gel  containing  4.87%  water. 
It  is  our  belief  that  with  an  anhy- 
drous gel  the  adsorption  of  ammonia 
will  be  found  to  be  in  accordance 
with  its  ease  of  condensation  as  expressed  by  its  critical  temperature. 

The  above  results  for  ammonia  must  also  be  corrected  for  the  acid  that 
is  present  in  the  gel.  In  the  beginning  it  was  thought  that  prolonged 
washing  with  distilled  water  was  sufficient  to  remove  all  acid,  especially 
inasmuch  as  the  acid  diffuses  readily  through  the  gel  when  in  the  state 
that  it  is  when  washed.  Nevertheless,  upon  collecting  the  liquid  that 
is  driven  off  from  a  gel  containing  .V21%  water  by  heating  to  800-900°, 
the  same  was  found  to  require  0.653  cc.  of  0.1066  7V  alkali  for  the  neutral- 
ization per  gram  of  gel.  This  acid  would  probably  not  exert  an  appre- 


11 


ciable  effect  upon  an  acidic  gas  such  as  sulfur  dioxide,  but  would  mate- 
rially affect  the  adsorption  of  ammonia. 

The  above  facts  illustrate  the  great  need  for  care  when  generalizations 
are  drawn  concerning  adsorption.  It  is  apparent  that  the  amount  of 
ammonia  that  the  gel  is  capable  of  taking  up  depends  not  only  on  the 
capillary  structure  of  the  gel,  but  in  addition  upon  the  water  and  acid 
content.  Before  generalizations  as  to  the  effect  of  capillarity  on  ad- 
sorption may  be  drawn,  it  is 
necessary  to  allow  for  the  1.4 
solubility  of  the  gas  in  the  ~Q 
water  and  the  amount  of  am-  _ 
monia  that  combines  with  2-6 
the  acid  present. 

If  instead  of  expressing  the 
weight  of  ammonia  taken  up 


3.4   3.8  2.2  2.6    1.0    1.4    1.8   0.2    0.6    0.1 


by  a  unit  weight  of  gel  under  a  certain  pressure,  the  volume  of  liquid 
ammonia  adsorbed  per  gram  of  gel  under  its  condensation  pressure  is 
used,  all  the  isotherms  fall  on  a  smooth  curve  which  may  be  expressed  by 
the  equation 


V=K(  —  ) 

•* 


These  results  are  shown  in  Fig.  4,  where  will  be  found 


plotted  the  logarithms  of  the  volume  of  ammonia  adsorbed  against  the 
logarithms  of  the  condensing  pressures   (P$/P0). 

A  similar  result  was  obtained  with  the  sulfur  dioxide  measurements 
where  the  values  of  K  and  l/N  were  0.1039  and  0.447,  respectively.  In 
the  case  of  ammonia  with  a  gel  of  4.88%  water  content,  the  equation 


becomes  V  =  0.1679  (  —  )  0.2105;  while  with  a  gel  of  0.33%  water  content 


K  has  the  value  of  0.0955  and  l/N  of  0.3588. 

At  first  thought  it  may  be  considered  strange  that  the  above  formula 
should  apply  to  the  adsorption  of  ammonia  when  we  consider  the  very 
large  portion  of  the  ammonia  that  is  dissolved  in  the  water  of  the  gel. 
This  behavior  is  immediately  explained,  however,  from  the  fact  that  the 
solubility  of  ammonia  in  water  may  be  expressed  by  the  same  formula 
that  is  used  to  express  the  results  of  the  adsorption  of  ammonia  by  silica 
gel.  In  other  words,  as  shown  by  measurements  made  in  this  laboratory, 
the  solubility  of  ammonia  in  water  is  well  represented  by  the  formula, 

V  =  . 

It  has  also  been  shown  that  the  solubility  of  sulfur  dioxide  in  water 
may  be  well  represented  by  the  above  formula  where  K  equals  0.0123 
and  l/N  equals  0.91.  It  is  therefore  possible  to  calculate  the  adsorption 


12 

due  to  the  capillary  structure  alone  by  correcting,  with  the  aid  of  the 
above  formula,  for  the  amount  of  gas  dissolved  in  the  water  of  the  gel. 

/P<r\l/N  /Pff\1/N' 

Applying  this  formula,  V=Kl  —  J  +0.04S#'( —  )  ,  to  the  measure- 
ments of  ammonia  made  with  the  gel  containing  4.8%  water,  the  value 
of  K  becomes  0.1147.  Doing  the  same  with  the  measurements  of  sulfur 
dioxide,  we  find  that  the  mean  value  for  K  does  not  differ  much  from 
0.1038.  The  K  for  the  anhydrous  gel  is  0.0955.  From  these  experiments 
we  see  that  the  amount  of  different  gases  adsorbed  due  to  capillarity  is 
in  good  agreement. 

Summary. 

1.  The  adsorption  of  ammonia  by  silica  gel  has  been  measured  under 
various  pressures  at  0°,  30°,  40°,  and  100°. 

2.  The  influence  of  the  water  content  of  the  gel  on  the  adsorption  has 
been  studied. 

3.  It  has  been  shown  that  the  adsorption  of  ammonia  may  be  satis- 
factorily explained  on  the  basis  of  capillary  condensation,  provided  cor- 
rections are  made  for  the  amount  of  the  gas  that  dissolves  in  the  water. 


BIOGRAPHY 

Levi  Yorgey  Davidheiser  was  born  at  New  Hanover,  Pa,  in  1885.  He 
received  his  elementary  education  in  the  schools  of  his  native  village, 
Boyertown  High  School  and  Perkiomen  School;  from  the  latter  institution 
he  was  graduated  in  1903.  He  then  took  up  the  teaching  profession,  in 
which  he  continued  until  1911  when  he  entered  Ursinus  College,  from 
which  institution  he  was  graduated  in  1914  with  the  degree  of  A.B.  He 
again  took  up  teaching.  In  1917  he  entered  the  graduate  school  of  Johns 
Hopkins  University,  following  the  subjects  of  Chemistry,  Physical  Chem- 
istry and  Mathematics.  During  the  year  1918-19  he  was  employed  by 
the  Aetna  Explosives  Co.,  Emporium,  Pa.,  as  head  chemist  of  the  acid 
laboratories.  In  the  fall  of  1919  he  again  took  up  his  work  at  Johns 
Hopkins  University,  completing  his  course  in  June,  1922. 


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'  ,j  ^ 

3MSZ 

i 

MAR  23  1942 

LD  21-100m-7,'40  (6936s) 

Pamphlet 

Binder 
Gaylord  Bros. 

Makers 
Syracuse,  N.  Y. 

PAT.  JAN  21,  "08 


)avidheiser 
Tha  adso 

imnonia  by 

•• 

(54 


silica  gel. 


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